Assessment of Storm Surge along the Coast of Central Vietnam

In the present paper, the interaction of surge, wave, and tide along the coast of central Vietnam is assessed using a coupled model of surge, wave, and tide. A series of storm surge simulations for Typhoons Xangsane (2006), Ketsana (2009), and Nary (2013) are carried out, considering the effects of tides and waves that combines wave-dependent drag and wave-induced radiation stress to find a predominant factor in storm surge generation. The results indicate that the surge–wave interaction is crucial to the storm surge simulation in this area. In particular, the wave-dependent drag improves an accuracy of the storm surge level up to 30%. In addition, the radiation stress contributes up to 15%. However, the tide–surge interaction is negligible because there is less than 2% difference in results with and without thetide. A series of coupled surge and wave simulations for 49 historical typhoons in the period of 1951 to 2014 show that mean peak surge levels along the coast are 2.5 m. The highest peak surge level reached 4.1 m at Cuaviet in the Quangtri
Province during Typhoon Harriet (1971).
ADDITIONAL INDEX WORDS: Typhoon; coupled model of surge, wave, and tide; interaction of surge.